Tube



June 3, 1930.

H. s. GILLETT TUBE Filed Dec; 1. 1927 [nae/afar. Jarr fl/ZW,

- U-NfiEnsrAT-ES PATENT OFFICE v 5.

' am? 3. drummer cnrcaeo, rumors; Ina LOUISE emm'rr, nxncnrarx or sun more - ly to the kind in which theseam is formed as 'a lock joint'and to the method of produemg It is an object Application ma December 1-, 19:21, ass-m. 237,000.

'lhe invention relates to tubing particular the same. v

of the'invention to provide a lock jointtube which is twisted in order to en'- ha'nce the ornamental appearance thereof. 1

It is a further object of the invention to ro'vide a'lock 'oint tube whichis reinforced y twisting sai tube, so that the-walls of sald tube are strengthened.

"Other and equally important objects will 7 become apparent from a perusal of the invention which comprises the means set forth in the specification, particularly polntedout in the claims forming a part thereof, and illustrated in the accompanying drawing, in

sstructed in accordance with my invention, Fig. 2 is a section on the line 2-2 of Fig.1,

Fig. 1 is an elevational view of a tube con- Fig.v 3 is'a fra mentary elevationalview of a slightly modi ed tube,

ing, 10,.generally design Fig. 4 is a section on the line 4+4 of Fig. 3. Referring to the several views of the drawates a tube which in the present instanceis hexagonal in cross section prioi'" to the twistingoperation which as shown has alread 'beenapplied thereto..

a lock joint andis particulai'ly-shown' in ,fidge ll of -the tubeisbent upon itself'to provide a pocket-12 to-receivethe.freeex- The tube is formed atiitsfmeetmg edges with tremity 1'3 of the edge 14 ofthetube so that this engagement'of the edges 11.and i is ef- "f vfi joint, yetthe edge 14' is free to slide on the I edge 11. or-vice versa, when suchsliding ;The' tube 15 is provided at diametricall opposite' points'with beads 18 and 19'whic are:

y prevented by reason of the lock movement is-necessa'ry or desirable.

of the tube 10 is-clamped in a head orchuck In order to provide-a-twisted tube, one end exerted until the tube is sufficiently twisted so that the corners of the hexagonal cross section change from lines parallel'to the axis to lines that follow a spiral course alongthe perimeter of'the tube. In this twisting 0 eration there occurs a shortening of the tube and this shortening is-made possible by reason of the fact that'the edges 11 and 14 slide- -on each other, thus facilitating the twisting process. .The tube, in addition "to its en-. hanced ornamental appearance is' simultane -ously reinforced, whereby it is enabled to withstand stresses or stra ns which'might be 1 GILLETT, DECEASED, ASSIGNOZB- TO EDWIN EL'IIRG} OF CHICAGO, ILLI- set up during use of the tube for the specific purpose to which it is assigned.

Hitherto twisted tubes have only been known to be madeby subjecting the tube to the action of surface rollers which impart to the surface of the tube indentations and ridges in simulation of a twisted-tube. But

an actual twisting'operation, as far as it is known, has never. been attempted because tubes with a welded seam could not be twisted'by. reason of the fact that it would cause anuneven distortion of the tube wall, so that the appearance of windin lines had to be created by an indentatio out, however, causing the longitudinal lines at the 'eriphery of the tube to lose their parallehtyto the central axis of the tube.

formation with In the present invention the main distinction 7 is predicated on the fact that the generatrices subsequent to the twisting operation lose their parallelity with the central axis of the tube course inthe form of. a;

and have a windin spiral iequidist'ant romkthe axis. throughout their length;

In Figs, san 4 a tat-15 is shown which has" a. circular cross sectionand-the edges 16 and 17' are interlocked; in the same manner as de-;

scribed for the precedin embodiment of the -invention,flafilording.a siding movement between'said edges under a twisting operation";

provided purely for. ornamental reasons. After a twisting operation has been earned tion t'o'the centralaxis to a win ing or spiral line equidistant throughout its len 11 from the axis. Thisis evident from the eads 18 and 19, which as shown in Fig. 3 appear as spiral beads winding on the tube and the 7 number of convolutions is determined by the duration of the torque applied to the free end of the tube while the other end is held securely a inst rotation.

While t e drawing shows preferred embodiments of the invention they are shown by way of example and not by way of limitation. It, therefore, is not my mtention of limiting the invention to the details as shown, nor to the sequence of steps of the method employed, but wish to include all changes and alterations constituting departures within the sco e of the invention as defined in the appende claims.

I claim:

1. The method of twisting a tube, including the steps of interlocking the longitudina edges so as to permit sliding of the edges on one another butpreventing lateral movement, and subjecting one end of said tube to a torque.

2. The method of twisting a tube, including the steps of arranging the longitudinal edges to sllde on one another but preventing lateral movement and subjecting one end of said tube to a tor no.

3. A tube having 1ts longitudinal edgessecured by a lock joint fprming a concealed seam within the periphery of the tube and extending spirally around the tube, said joint permitting longitudinal movement but preventin relative lateral movement of the tube e ges. c

In witness whereof I afiix my signature.

HARRY S. GILLETT. 

